Ionic gels with the capacity to absorb a thousand times their dry weight in water are widely used for diapers and as water absorbents in medical, chemical, and agricultural applications. The dramatic swelling power of these superabsorbent gels is a result of the electrostatic repulsion between the charges along the polymer chains and of the osmotic pressure of the counter ions. It is known, however, that this swelling power is drastically diminished in salt solutions such as saline, urine, or blood. They are no longer super-absorbents in the presence of such physiologic fluids.
Dissolved salts such as Na.sup.+ and Cl.sup.- ions have two effects on ionic gels. They screen the polymer charges and they eliminate the osmotic imbalance due to the presence of counter ions in and out of the gel. Dissolved ions effectively convert an ionic gel into a non-ionic gel whereby the swelling power is lost. This has long been a serious problem in medical polymer technology. We demonstrate general methods and representative compositions that eliminate the screening effect of the dissolved salt.